[331] | 1 | /*
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| 2 | * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
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| 3 | *
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| 4 | * Licensed under the OpenSSL license (the "License"). You may not use
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| 5 | * this file except in compliance with the License. You can obtain a copy
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| 6 | * in the file LICENSE in the source distribution or at
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| 7 | * https://www.openssl.org/source/license.html
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| 8 | */
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| 9 |
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| 10 | #include <stdio.h>
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| 11 | #include <errno.h>
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| 12 | #include "internal/cryptlib.h"
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| 13 | #include <openssl/buffer.h>
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| 14 | #include <openssl/evp.h>
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| 15 | #include "internal/bio.h"
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| 16 |
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| 17 | static int enc_write(BIO *h, const char *buf, int num);
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| 18 | static int enc_read(BIO *h, char *buf, int size);
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| 19 | /*
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| 20 | * static int enc_puts(BIO *h, const char *str);
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| 21 | */
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| 22 | /*
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| 23 | * static int enc_gets(BIO *h, char *str, int size);
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| 24 | */
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| 25 | static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2);
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| 26 | static int enc_new(BIO *h);
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| 27 | static int enc_free(BIO *data);
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| 28 | static long enc_callback_ctrl(BIO *h, int cmd, bio_info_cb *fps);
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| 29 | #define ENC_BLOCK_SIZE (1024*4)
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| 30 | #define ENC_MIN_CHUNK (256)
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| 31 | #define BUF_OFFSET (ENC_MIN_CHUNK + EVP_MAX_BLOCK_LENGTH)
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| 32 |
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| 33 | typedef struct enc_struct {
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| 34 | int buf_len;
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| 35 | int buf_off;
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| 36 | int cont; /* <= 0 when finished */
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| 37 | int finished;
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| 38 | int ok; /* bad decrypt */
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| 39 | EVP_CIPHER_CTX *cipher;
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| 40 | unsigned char *read_start, *read_end;
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| 41 | /*
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| 42 | * buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate can return
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| 43 | * up to a block more data than is presented to it
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| 44 | */
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| 45 | unsigned char buf[BUF_OFFSET + ENC_BLOCK_SIZE];
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| 46 | } BIO_ENC_CTX;
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| 47 |
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| 48 | static const BIO_METHOD methods_enc = {
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| 49 | BIO_TYPE_CIPHER, "cipher",
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| 50 | enc_write,
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| 51 | enc_read,
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| 52 | NULL, /* enc_puts, */
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| 53 | NULL, /* enc_gets, */
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| 54 | enc_ctrl,
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| 55 | enc_new,
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| 56 | enc_free,
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| 57 | enc_callback_ctrl,
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| 58 | };
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| 59 |
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| 60 | const BIO_METHOD *BIO_f_cipher(void)
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| 61 | {
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| 62 | return (&methods_enc);
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| 63 | }
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| 64 |
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| 65 | static int enc_new(BIO *bi)
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| 66 | {
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| 67 | BIO_ENC_CTX *ctx;
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| 68 |
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| 69 | ctx = OPENSSL_zalloc(sizeof(*ctx));
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| 70 | if (ctx == NULL)
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| 71 | return 0;
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| 72 |
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| 73 | ctx->cipher = EVP_CIPHER_CTX_new();
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| 74 | if (ctx->cipher == NULL) {
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| 75 | OPENSSL_free(ctx);
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| 76 | return 0;
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| 77 | }
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| 78 | ctx->cont = 1;
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| 79 | ctx->ok = 1;
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| 80 | ctx->read_end = ctx->read_start = &(ctx->buf[BUF_OFFSET]);
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| 81 | BIO_set_data(bi, ctx);
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| 82 | BIO_set_init(bi, 1);
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| 83 |
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| 84 | return 1;
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| 85 | }
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| 86 |
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| 87 | static int enc_free(BIO *a)
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| 88 | {
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| 89 | BIO_ENC_CTX *b;
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| 90 |
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| 91 | if (a == NULL)
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| 92 | return 0;
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| 93 |
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| 94 | b = BIO_get_data(a);
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| 95 | if (b == NULL)
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| 96 | return 0;
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| 97 |
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| 98 | EVP_CIPHER_CTX_free(b->cipher);
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| 99 | OPENSSL_clear_free(b, sizeof(BIO_ENC_CTX));
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| 100 | BIO_set_data(a, NULL);
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| 101 | BIO_set_init(a, 0);
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| 102 |
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| 103 | return 1;
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| 104 | }
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| 105 |
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| 106 | static int enc_read(BIO *b, char *out, int outl)
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| 107 | {
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| 108 | int ret = 0, i, blocksize;
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| 109 | BIO_ENC_CTX *ctx;
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| 110 | BIO *next;
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| 111 |
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| 112 | if (out == NULL)
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| 113 | return (0);
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| 114 | ctx = BIO_get_data(b);
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| 115 |
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| 116 | next = BIO_next(b);
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| 117 | if ((ctx == NULL) || (next == NULL))
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| 118 | return 0;
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| 119 |
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| 120 | /* First check if there are bytes decoded/encoded */
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| 121 | if (ctx->buf_len > 0) {
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| 122 | i = ctx->buf_len - ctx->buf_off;
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| 123 | if (i > outl)
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| 124 | i = outl;
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| 125 | memcpy(out, &(ctx->buf[ctx->buf_off]), i);
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| 126 | ret = i;
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| 127 | out += i;
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| 128 | outl -= i;
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| 129 | ctx->buf_off += i;
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| 130 | if (ctx->buf_len == ctx->buf_off) {
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| 131 | ctx->buf_len = 0;
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| 132 | ctx->buf_off = 0;
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| 133 | }
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| 134 | }
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| 135 |
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| 136 | blocksize = EVP_CIPHER_CTX_block_size(ctx->cipher);
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| 137 | if (blocksize == 1)
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| 138 | blocksize = 0;
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| 139 |
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| 140 | /*
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| 141 | * At this point, we have room of outl bytes and an empty buffer, so we
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| 142 | * should read in some more.
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| 143 | */
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| 144 |
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| 145 | while (outl > 0) {
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| 146 | if (ctx->cont <= 0)
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| 147 | break;
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| 148 |
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| 149 | if (ctx->read_start == ctx->read_end) { /* time to read more data */
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| 150 | ctx->read_end = ctx->read_start = &(ctx->buf[BUF_OFFSET]);
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| 151 | i = BIO_read(next, ctx->read_start, ENC_BLOCK_SIZE);
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| 152 | if (i > 0)
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| 153 | ctx->read_end += i;
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| 154 | } else {
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| 155 | i = ctx->read_end - ctx->read_start;
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| 156 | }
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| 157 |
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| 158 | if (i <= 0) {
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| 159 | /* Should be continue next time we are called? */
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| 160 | if (!BIO_should_retry(next)) {
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| 161 | ctx->cont = i;
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| 162 | i = EVP_CipherFinal_ex(ctx->cipher,
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| 163 | ctx->buf, &(ctx->buf_len));
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| 164 | ctx->ok = i;
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| 165 | ctx->buf_off = 0;
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| 166 | } else {
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| 167 | ret = (ret == 0) ? i : ret;
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| 168 | break;
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| 169 | }
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| 170 | } else {
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| 171 | if (outl > ENC_MIN_CHUNK) {
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| 172 | /*
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| 173 | * Depending on flags block cipher decrypt can write
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| 174 | * one extra block and then back off, i.e. output buffer
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| 175 | * has to accommodate extra block...
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| 176 | */
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| 177 | int j = outl - blocksize, buf_len;
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| 178 |
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| 179 | if (!EVP_CipherUpdate(ctx->cipher,
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| 180 | (unsigned char *)out, &buf_len,
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| 181 | ctx->read_start, i > j ? j : i)) {
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| 182 | BIO_clear_retry_flags(b);
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| 183 | return 0;
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| 184 | }
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| 185 | ret += buf_len;
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| 186 | out += buf_len;
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| 187 | outl -= buf_len;
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| 188 |
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| 189 | if ((i -= j) <= 0) {
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| 190 | ctx->read_start = ctx->read_end;
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| 191 | continue;
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| 192 | }
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| 193 | ctx->read_start += j;
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| 194 | }
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| 195 | if (i > ENC_MIN_CHUNK)
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| 196 | i = ENC_MIN_CHUNK;
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| 197 | if (!EVP_CipherUpdate(ctx->cipher,
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| 198 | ctx->buf, &ctx->buf_len,
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| 199 | ctx->read_start, i)) {
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| 200 | BIO_clear_retry_flags(b);
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| 201 | ctx->ok = 0;
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| 202 | return 0;
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| 203 | }
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| 204 | ctx->read_start += i;
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| 205 | ctx->cont = 1;
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| 206 | /*
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| 207 | * Note: it is possible for EVP_CipherUpdate to decrypt zero
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| 208 | * bytes because this is or looks like the final block: if this
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| 209 | * happens we should retry and either read more data or decrypt
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| 210 | * the final block
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| 211 | */
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| 212 | if (ctx->buf_len == 0)
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| 213 | continue;
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| 214 | }
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| 215 |
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| 216 | if (ctx->buf_len <= outl)
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| 217 | i = ctx->buf_len;
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| 218 | else
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| 219 | i = outl;
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| 220 | if (i <= 0)
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| 221 | break;
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| 222 | memcpy(out, ctx->buf, i);
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| 223 | ret += i;
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| 224 | ctx->buf_off = i;
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| 225 | outl -= i;
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| 226 | out += i;
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| 227 | }
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| 228 |
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| 229 | BIO_clear_retry_flags(b);
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| 230 | BIO_copy_next_retry(b);
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| 231 | return ((ret == 0) ? ctx->cont : ret);
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| 232 | }
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| 233 |
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| 234 | static int enc_write(BIO *b, const char *in, int inl)
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| 235 | {
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| 236 | int ret = 0, n, i;
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| 237 | BIO_ENC_CTX *ctx;
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| 238 | BIO *next;
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| 239 |
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| 240 | ctx = BIO_get_data(b);
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| 241 | next = BIO_next(b);
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| 242 | if ((ctx == NULL) || (next == NULL))
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| 243 | return 0;
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| 244 |
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| 245 | ret = inl;
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| 246 |
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| 247 | BIO_clear_retry_flags(b);
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| 248 | n = ctx->buf_len - ctx->buf_off;
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| 249 | while (n > 0) {
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| 250 | i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
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| 251 | if (i <= 0) {
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| 252 | BIO_copy_next_retry(b);
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| 253 | return (i);
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| 254 | }
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| 255 | ctx->buf_off += i;
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| 256 | n -= i;
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| 257 | }
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| 258 | /* at this point all pending data has been written */
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| 259 |
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| 260 | if ((in == NULL) || (inl <= 0))
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| 261 | return (0);
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| 262 |
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| 263 | ctx->buf_off = 0;
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| 264 | while (inl > 0) {
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| 265 | n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl;
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| 266 | if (!EVP_CipherUpdate(ctx->cipher,
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| 267 | ctx->buf, &ctx->buf_len,
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| 268 | (const unsigned char *)in, n)) {
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| 269 | BIO_clear_retry_flags(b);
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| 270 | ctx->ok = 0;
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| 271 | return 0;
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| 272 | }
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| 273 | inl -= n;
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| 274 | in += n;
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| 275 |
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| 276 | ctx->buf_off = 0;
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| 277 | n = ctx->buf_len;
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| 278 | while (n > 0) {
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| 279 | i = BIO_write(next, &(ctx->buf[ctx->buf_off]), n);
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| 280 | if (i <= 0) {
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| 281 | BIO_copy_next_retry(b);
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| 282 | return (ret == inl) ? i : ret - inl;
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| 283 | }
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| 284 | n -= i;
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| 285 | ctx->buf_off += i;
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| 286 | }
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| 287 | ctx->buf_len = 0;
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| 288 | ctx->buf_off = 0;
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| 289 | }
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| 290 | BIO_copy_next_retry(b);
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| 291 | return (ret);
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| 292 | }
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| 293 |
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| 294 | static long enc_ctrl(BIO *b, int cmd, long num, void *ptr)
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| 295 | {
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| 296 | BIO *dbio;
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| 297 | BIO_ENC_CTX *ctx, *dctx;
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| 298 | long ret = 1;
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| 299 | int i;
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| 300 | EVP_CIPHER_CTX **c_ctx;
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| 301 | BIO *next;
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| 302 |
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| 303 | ctx = BIO_get_data(b);
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| 304 | next = BIO_next(b);
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| 305 | if (ctx == NULL)
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| 306 | return 0;
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| 307 |
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| 308 | switch (cmd) {
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| 309 | case BIO_CTRL_RESET:
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| 310 | ctx->ok = 1;
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| 311 | ctx->finished = 0;
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| 312 | if (!EVP_CipherInit_ex(ctx->cipher, NULL, NULL, NULL, NULL,
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| 313 | EVP_CIPHER_CTX_encrypting(ctx->cipher)))
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| 314 | return 0;
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| 315 | ret = BIO_ctrl(next, cmd, num, ptr);
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| 316 | break;
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| 317 | case BIO_CTRL_EOF: /* More to read */
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| 318 | if (ctx->cont <= 0)
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| 319 | ret = 1;
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| 320 | else
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| 321 | ret = BIO_ctrl(next, cmd, num, ptr);
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| 322 | break;
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| 323 | case BIO_CTRL_WPENDING:
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| 324 | ret = ctx->buf_len - ctx->buf_off;
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| 325 | if (ret <= 0)
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| 326 | ret = BIO_ctrl(next, cmd, num, ptr);
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| 327 | break;
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| 328 | case BIO_CTRL_PENDING: /* More to read in buffer */
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| 329 | ret = ctx->buf_len - ctx->buf_off;
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| 330 | if (ret <= 0)
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| 331 | ret = BIO_ctrl(next, cmd, num, ptr);
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| 332 | break;
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| 333 | case BIO_CTRL_FLUSH:
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| 334 | /* do a final write */
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| 335 | again:
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| 336 | while (ctx->buf_len != ctx->buf_off) {
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| 337 | i = enc_write(b, NULL, 0);
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| 338 | if (i < 0)
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| 339 | return i;
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| 340 | }
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| 341 |
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| 342 | if (!ctx->finished) {
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| 343 | ctx->finished = 1;
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| 344 | ctx->buf_off = 0;
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| 345 | ret = EVP_CipherFinal_ex(ctx->cipher,
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| 346 | (unsigned char *)ctx->buf,
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| 347 | &(ctx->buf_len));
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| 348 | ctx->ok = (int)ret;
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| 349 | if (ret <= 0)
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| 350 | break;
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| 351 |
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| 352 | /* push out the bytes */
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| 353 | goto again;
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| 354 | }
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| 355 |
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| 356 | /* Finally flush the underlying BIO */
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| 357 | ret = BIO_ctrl(next, cmd, num, ptr);
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| 358 | break;
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| 359 | case BIO_C_GET_CIPHER_STATUS:
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| 360 | ret = (long)ctx->ok;
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| 361 | break;
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| 362 | case BIO_C_DO_STATE_MACHINE:
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| 363 | BIO_clear_retry_flags(b);
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| 364 | ret = BIO_ctrl(next, cmd, num, ptr);
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| 365 | BIO_copy_next_retry(b);
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| 366 | break;
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| 367 | case BIO_C_GET_CIPHER_CTX:
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| 368 | c_ctx = (EVP_CIPHER_CTX **)ptr;
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| 369 | *c_ctx = ctx->cipher;
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| 370 | BIO_set_init(b, 1);
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| 371 | break;
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| 372 | case BIO_CTRL_DUP:
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| 373 | dbio = (BIO *)ptr;
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| 374 | dctx = BIO_get_data(dbio);
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| 375 | dctx->cipher = EVP_CIPHER_CTX_new();
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| 376 | if (dctx->cipher == NULL)
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| 377 | return 0;
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| 378 | ret = EVP_CIPHER_CTX_copy(dctx->cipher, ctx->cipher);
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| 379 | if (ret)
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| 380 | BIO_set_init(dbio, 1);
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| 381 | break;
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| 382 | default:
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| 383 | ret = BIO_ctrl(next, cmd, num, ptr);
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| 384 | break;
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| 385 | }
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| 386 | return (ret);
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| 387 | }
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| 388 |
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| 389 | static long enc_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)
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| 390 | {
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| 391 | long ret = 1;
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| 392 | BIO *next = BIO_next(b);
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| 393 |
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| 394 | if (next == NULL)
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| 395 | return (0);
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| 396 | switch (cmd) {
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| 397 | default:
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| 398 | ret = BIO_callback_ctrl(next, cmd, fp);
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| 399 | break;
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| 400 | }
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| 401 | return (ret);
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| 402 | }
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| 403 |
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| 404 | /*-
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| 405 | void BIO_set_cipher_ctx(b,c)
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| 406 | BIO *b;
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| 407 | EVP_CIPHER_ctx *c;
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| 408 | {
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| 409 | if (b == NULL) return;
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| 410 |
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| 411 | if ((b->callback != NULL) &&
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| 412 | (b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,0L) <= 0))
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| 413 | return;
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| 414 |
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| 415 | b->init=1;
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| 416 | ctx=(BIO_ENC_CTX *)b->ptr;
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| 417 | memcpy(ctx->cipher,c,sizeof(EVP_CIPHER_CTX));
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| 418 |
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| 419 | if (b->callback != NULL)
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| 420 | b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,1L);
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| 421 | }
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| 422 | */
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| 423 |
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| 424 | int BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k,
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| 425 | const unsigned char *i, int e)
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| 426 | {
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| 427 | BIO_ENC_CTX *ctx;
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| 428 | long (*callback) (struct bio_st *, int, const char *, int, long, long);
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| 429 |
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| 430 | ctx = BIO_get_data(b);
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| 431 | if (ctx == NULL)
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| 432 | return 0;
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| 433 |
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| 434 | callback = BIO_get_callback(b);
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| 435 |
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| 436 | if ((callback != NULL) &&
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| 437 | (callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e,
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| 438 | 0L) <= 0))
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| 439 | return 0;
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| 440 |
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| 441 | BIO_set_init(b, 1);
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| 442 |
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| 443 | if (!EVP_CipherInit_ex(ctx->cipher, c, NULL, k, i, e))
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| 444 | return 0;
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| 445 |
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| 446 | if (callback != NULL)
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| 447 | return callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L);
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| 448 | return 1;
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| 449 | }
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